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County Commissioners will award the bid for a new 700/800MHz P25 Digital Radio System on Tuesday, March 1st, 2011. The current radio system is the older Analog Motorola Type II Smartnet system. This system is shared by all Federal, State, County and City Police agencies, County, City and area Volunteer Fire Departments, the county's Emergency Medical Service as well as public works.

In the present 800 MHz trunked radio system, it is impossible to control who
monitors calls outside of the network. Command and investigative conversations may
involve topics of a legally restricted or sensitive nature where eavesdropping by outside,
unidentified persons is undesirable or unacceptable.
Accordingly, the new digital voice radio network shall include provisions for call
privacy whereby identified users within the network can be excluded from certain talk groups
or individual conversations. This provision must offer sufficient flexibility such that the
desirable features of monitoring can be retained while permitting privacy to conversations
that are potentially confidential. Finally, the new network shall incorporate technical features
that prevent unauthorized listeners from monitoring any network calls. Ideally, the new
network should inhibit the ability of non-network users from monitoring actual voice
transmissions of any type (inclusive of telephone interconnect calls) as well as preventing
such persons from monitoring those call assignments transacted via the network’s digital

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control channel.
Proposers should describe the scope and operation of such provisions inherent within
their proposed solution that prevent the types of undesired radio monitoring discussed above.

3.2.4 Encryption

Digital voice encryption, using Improved Multi-band Excited (IMBE) as well as
Advanced Multi-Band Excited (AMBE) vocoder technology coupled with federally approved
digital encryption schemes, is a required feature of the new network. All proposed
encryption should be to APCO Project 25 Standards.
Three modes of encrypted digital voice operation are desired:
3.2.4.1. Unit-to-unit, where conversations in an encrypted talk group are
secure. These can be monitored at a dispatch or control point.
3.2.4.2. Dispatcher-to-unit, where conversations between the County’s
Communication Center, Backup Center(s) and field units are secure.
3.2.4.3. Unit-to-telephone network, where conversations between encrypted
units and the switched telephone network are secure.
The new network will provide encrypted transmission so that system access delays
are equal to those in the clear mode. Encrypted transmissions will not degrade the operation
of clear-voice features nor lengthen system access or audio transport delays to other users.

Encryption shall not degrade the range or coverage less than normal digital performance.